Ideal Flow Reactors - Bioprocess Engineering: Kinetics, Biosystems, Sustainability and Reactor Design - page 246

2 min 1 (a) 90% conversion, k ¼

2mol $ L 1 $ min 1

(b) 99% conversion, k ¼

2 mol $ L 1 $ min 1 (c) 99.9% conversion, k ¼

2 min 1 $ L $ mol 1 (d) 90% conversion, k ¼

$ L $ mol 1
5.6. Set up the above problems if the feed is pure A, A and B are ideal gases, and the reactors
operate at 100 atm.
5.7. An aqueous feed containing reactant A (1 mol/L) enters a 2-L plug flow reactor and
reacts with the reaction 2A

2 min 1 (e) 99.9% conversion, k

¼

0.2 C A .
(a) What feed rate (L/min) will give an outlet concentration of C A ¼

/ B, r (mol/L/min) ¼

0.1 mol/L?
(b) Find the outlet concentration of A (mol/L) for a feed rate of 0.1 L/min.
(c) Repeat this problem for a stirred-tank reactor.
5.8. An aqueous feed containing reactant A at C A0 ¼ 100 mol/

min decomposes in a CSTR to give a variety of products. The kinetics of the conversion
are represented by

2 mol/L at a feed rate F A0 ¼

r ¼ 10 C A mol $ L 1 $ min 1

A / 2:5 B ;

(a) Find the volume CSTR needed for 80% decomposition of reactant A .
(b) Find the conversion in a 30 L CSTR.
(c) What flow rate will be required to produce 100 mol/min of B at 80% conversion?
5.9. An ester in aqueous solution is to be saponified in a continuous reactor system.
Batch experiments showed that the reaction is first order and irreversible, and 50%
reaction occurred in 8 min at the temperature required. We need to process
100 mol/h of 4 mol/L feed to 95% conversion. Calculate the reactor volumes
required for this process in
(a) a PFR,
(b) a CSTR,
(c) two equal-volume CSTRs,
(d) four equal-volume CSTRs.
5.10. The aqueous reaction A

C A ) 2 (rate in / products has a rate r ¼ 2C A /(1 þ

$ min 1 ) and is to be carried out in a continuous reactor system. We need to
process 100 mol/h of 2 mol/L feed to 90% conversion. Calculate the reactor volumes
required in
(a) a PFR,
(b) a CSTR,
(c) two equal-volume CSTRs.
(d) Use plots of 1/ r vs conversion to show these results.
(e) What is the ideal combination of reactors for total minimum volume for this reaction?
(f) Show how you would solve problem (e) analytically. Set up equations and indicate
the method of solution.
5.11. We have a 100-gal tank of a product that now contains small particles that must be
removed before it can be sold. The product now has 10 4 particles/cm 3 , and it is only
acceptable for sale if the particle concentration is less than 10 2 particles/cm 3 . We have
a filter that will effectively remove all particles.

mol $ L 1